Simple Precision Creation of Digitally Specified, Spatially Heterogeneous, Engineered Tissue Architectures

Complex architectures of integrated circuits are achieved through multiple layer photolithography, which has empowered the semiconductor industry. We adapt this philosophy for tissue engineering with a versatile, scalable, and generalizable microfabrication approach to create engineered tissue architectures composed of digitally specifiable building blocks, each with tuned structural, cellular, and compositional features.Paul G. Allen Family FoundationNew York Stem Cell FoundationNational Institutes of Health (U.S.)National Science Foundation (U.S.)Lincoln LaboratoryInstitution of Engineering and Technology (AF Harvey Prize

Oxidation Behavior of C- and Au-Ion-Implanted Biodegradable Polymers

WOS: 000301521200008Biodegradable polymers are widely used in biomedical and tissue engineering applications due to their biocompatibility and hydrolysis properties in the body. However, their low surface energy and lack of functional groups to interact with the cellular environment have limited their applications for in vivo studies. Ion beam modification is a convenient method for improving the surface properties of polymeric materials for functional biomedical applications. In the work described here, vacuum arc metal ion implantation was used to modify the composition of the near-surface region of three kinds of polymers-poly(L-lactide), poly(D, L-lactide-co-glycolide), and poly(L-lactide/caprolactone)-chosen as representative of biodegradable polymers. X-ray photoelectron spectroscopy analysis was used to characterize the chemical effects of these polymers after implantation with C and with Au, and the results were compared with untreated control samples. We find that oxidation behavior is brought about for certain implantation fluences, resulting in improved surface hydrophilicity

The Effect of Ag and Ag plus N Ion Implantation on Cell Attachment Properties

20th International Conference on Application of Accelerators in Research and Industry -- AUG 10-15, 2008 -- Ft Worth, TXWOS: 000265828500115Implanted biomedical prosthetic devices are intended to perform safely, reliably and effectively in the human body thus the materials used for orthopedic devices should have good biocompatibility. Ultra High Molecular Weight Poly Ethylene (UHMWPE) has been commonly used for total hip joint replacement because of its very good properties. In this work, UHMWPE samples were Ag and Ag+N ion implanted by using the Metal-Vapor Vacuum Arc (MEVVA) ion implantation technique. Samples were implanted with a fluency of 1017 ion/cm2 and extraction voltage of 30 kV. Rutherford Backscattering Spectrometry (RBS) was used for surface studies. RBS showed the presence of Ag and N on the surface. Cell attachment properties investigated with model cell lines (L929 mouse fibroblasts) to demonstrate that the effect of Ag and Ag+N ion implantation can favorably influence the surface of UHMWPE for biomedical applications. Scanning electron microscopy (SEM) was used to demonstrate the cell attachment on the surface. Study has shown that Ag+N ion implantation represents more effective cell attachment properties on the UHMWPE surfaces.Univ N Texas, Sandia Natl La

Modification of surface morphology of UHMWPE for biomedical implants

Symposium on Ion-Beam-Based Nanofabrication held at the 2007 MRS Spring Meeting -- APR 10-12, 2007 -- San Francisco, CAWOS: 000250475100012Ultra High Molecular Weight Polyethylene (UHMWPE) samples were implanted with metal and metal-gas hybrid ions (Ag, Ag+N, C+H, C+H+Ar, Ti+O) by using improved MEVVA Ion implantation technique [1,2]. An extraction voltage of 30 kV and influence of 1017 ions/cm2 were attempted in this experiment. to change their surface morphologies in order to understand the effect of ion implantation on the surface properties of UHMWPEs. Characterizations of the implanted samples with RBS, ATR - FTIR, spectra were compared with the un-implanted ones. Implanted and unimplanted samples were also thermally characterized by TGA and DSC. It was generally observed that C-H bond concentration seemed to be decreasing with ion implantation and the results indicated that the chain structure of UHMWPE were changed and crosslink density and polymer crystallinity were increased compared to unimplanted ones resulting in increased hardness. It was also observed that nano size cracks (approx. 10nm) were significantly disappeared after Ag implantation, which also has an improved antibacterial effect. Contact angle measurements showed that wettability of samples increased with ion implantation. Results showed that metal and metal+gas hybrid ion implantation could be an effective way to improve the surface properties of UHMWPE to be used in hip and knee prosthesis.Center for Irradiation of Materials, Alabama AM UniversityThis work was supported by the Center for Irradiation of Materials, Alabama A&M University